Electric switch



G. B THOMAS ELECTRIC SWI-TCH Filed April l3, 1922 HIIHHHHI? v INVENTOR G0RGE 5. Two/was Y ATTORNEYS Patented May 10, 1927.-

UNITED STATES PATENT. OFFICE.

enonen -12. THOMAS, or iamncnronr, connnc'rrourr, AssIGNoR TO THE BRYANT on emnenrom',

nnnor uc COMPANY, nncrroccr.

ELECTRIC SWITCH.

CONNECTICUT, A CORPORATION OF CON- App llcation filed April 13, 1922. Serial No. 552,225.

' My invention relates to electric switches,

and particularly to a switch mechanism of the, quick make and break type adapted to control lighting circuits and the like. The

object of my invention is to provide a mechanism of this sort in which the switch opening moven'ien't of the commutator is .positively initiated while still maintainingthe advantage of spring action for effecting quick throw of the commutator to break the circuit.

In the accompanying drawings Fig. 1 is a-vertical section through an electric lamp socket in which a switch embodying my invention is illustrated;

Fig. 2 is a plan view thereof with the upper insulating button of the socket body removed; I

Fig. 3 is a section on the line 33, Fig. 2', and

Figs. 4 and 5 are similar views showing the switch mechanism at different stages of operation.

In its main features, the present switch resembles that shown in the patent to De- Reamer No. 1,059,846, and for convenience is illustrated in an electric lamp socket. As in that construction, the socket body comprises a pair of insulating buttons 6 and 7, suitb ably recessed on their adjacent faces to form a switch chamber. On the button 7 is mounts ed the usual screw shell contact 8, which is held in position by the flange '9 of the wire terminal bracket 10, secured on the-button 7 by screw bolts (not shown) passing- .through holes 11 and 12 in the buttons 6 and 7 The center contact 13 is secured by a rivet 14 to the base of the switch contact 151whichcooperate's with a second contact- 16 secured beneath the wire termlnal bracket 17. The commutator or switch bar 18 is of U-shape and bridges the contacts and 16 in circuit-closing position, the switch mechanism servino to throw'it to the position indicated in dbtted lines in Fig. 3 to open the circuit. The commutator is pivoted at- 19 on the frame member 20 carried by the b'ut-' ton 7 and pierced to afford bearings for the switch operating spindle 21, actuated by the thumb piece 22 fast thereon.

At the inner end of the spindle 21 is a crank arm 23 having an offset stud 24, against which the head 25 of the pin 26 is seated by the switch-operating coil spring 27. The opposite end of 'the latter bears crank arm spring 27 across the axis of oscillation ofagainst the bridge either direction.

against the free and surrounds thereon.

-The axis 19 on which the commutator rocks, intersects that of the spindle 21. Consequently, when the spindle is rotated, its 23 shifts the crank end of the end of the commutator 18 an I inwardly struck boss 28 the commutator. The biasing effort of the spring, which bears at its opposite end the latter is thrown with snap action from c rcuit closing to open circuit position, or VICBVGISa, on the rotation of the spindle in In the construction shown in the De Reamer patent-above mentioned, the pin 26 is carried freely through the bridge end of .the commutator and serve: no other func tion than that of a guide for the switch actuating spring 27. .The biasing action of the spring thus constitutes the sole means for oscillating the commutator to make or break the circuit through the switch. It not infrequently happens, however, that the surfaces of the contacts 15 and 16, or the cooperating surface of the ecome oxidized. Under such conditions, or even when the contacts 15 and 16 are set too close together during assembly, the friction between the engaging surfaces may be sufend of the commutator, isthuseXerted in the opposite directio and commutator itself,

ficient to overcome the biasing effort of the switch spring, and consequently the rotation of the switch spindle 21 fails to throw the switch to open circuit position. I have remedied this defect in the mechanism by so constructing the parts that the movement of thecolnmutator is positively initiated, while the biasing action of the spring is still maintained to effect the snap action of the mechanism.

For this purpose I utilize the pin 26 as a thrust member which positively engages the commutator-on the rotation of the spindle,

and forces it from its extreme position at one side-or the other of its axis of oscil--- lation. It is of course. obvious that. the crank arm stud 24 rotates in a plane, and that ,the bridge 18 of the commutator rocks on an arc the prolongation'of which intersects the plane of rotation of the stud 24. Furthermore, when the parts are in a posi tion of rest (Fig. 3) the stud 24 and the commutator bridge 18 he on opposite sides with of the axis of oscillation l9 oi the latter, and are spaced as far apart (under the pressure of the spring 27) as the construction and arrangement of the switch mechanism permits. It will ,be noted that in this position the free end of the thrust pin 26 is spaced from the boss 28 of the bridge 18.

As the spindle 18 is rotated, however, the crank arm stud moves downward in its plane of rotation,and eventually across the axis of oscillation of the commutator to 'a point at which its distance from the commutator bridge is materially less than that at which these parts are spaced in the position of rest. During this downward movement of the stud, the free end of the pin 26 gradually approaches the boss 28 on the commutator bridge, and approximately as the crank arm crosses, the axis of oscillation 19 the pin end engages the boss 28 (Fig. 4). On further rotation of the spindle, in the same direction, the'pin 26, now acting as a rigid strut betweenthe crank arm and the bridge 18, forces the latter to swing outward on its axis away from the plane of rotation of the crank arm, and thus positively frees it from engagemen be tween the contacts 15 and 16 (Fig. 5). In-

asmuch as the stress on the spring Q'Zhas been simultaneously increased, and its biasing efl'ort is in opposite direction, owing to the fact that its abutment (the crank arm) has been shifted across the .axis of oscillation of thecommutator, the latter is now thrown with snap action toopen circuit position (Fig. 3, dotted lines).

The particular construction of the pin and abutment upon the commutator may be variously modified, as well as of its bearing the proportions between-these parts and the crank arm 23. The mechanism is not limited in its utility to an electric socket switch, and may be applied to other devices as well.

The angular throw of the commutator may be limited in many ways. its legs extended beyond the pivot axis 19 to form stop wings 29, which work between the base of the frame 20 and stop lugs 30 oliset from the top of one of the frame uprights.

Various modifications in detail and arme'mber oscillatin tion of said mem er andon an are inter- I have shown Leases-o rangement oi"; the parts will readily occur to those skilled in the art, which do not depart from what I claim as my invention,

1 claim- 1. A mechanical movement for electric switches and the like, comprising a. member rotating substantially in a lane, a pivoted member oscillatin across tie axis of rotation of said member and on an are intersecting said plane, and, a bodily movable thrust member hearing at one end against said rotating member and normally out of but moving into positive displacing engagement with said pivoted member when said rotating and ivoted members are brought to the same side. of the axis of the rotary member by the relative displacement of said rotary member with respect to said pivoted member.

2. A mechanical movement for electric switches and the like, comprising a member rotating substantially in a plane, a pivoted across t c axis of rotasecting said plane, and a thrust member hearing at one end against said rotating member and normally spaced from said pivoted member, but moving into operative engagementswith the latter when said rotating and pivoted members are brought to the same side ofthe axis of the rotary member bv the relative displacement of said rotating member with respect to said pivoted member, together with a spring interposed between said rotatin and oscillating mem-,

bers, and stressed liy the rotation of the former.

3. In an electric switch, a rotary switch spindle, tatingsubstantially in a plane, a commutator pivoted to oscillate across the axis of said spindle, a spring interposed between said crank arm and commutator for imparting a quick throw to the latter, anda thrust rod having a thrust engagement with said commutator on the rotation of the crank to the sameside of its axis of rotaacrank operated thereby and rotion as that on which the commutator lies. I

In testimony whereof I have signed my name to this specification.

GEORGE B. THOMAS. 

